For the purpose of automatically releasing a ski boot from a ski, use has been made of safety ski bindings in which, when a pressure exceeding a given, possibly adjustable resistance comes into play, a ski boot holder moves from its locking positon to its releasing position, thus releasing the ski boot. Hitherto known ski safety bindings are triggered on the principle of a mechanical elasticity prescribed by a force/distance function. However, distance has proved to be a very critical and unreliable parameter which very decisively depends on environmental influences that have a large effect on friction. Kinematic design and choice of material also decide the actuating behaviour and thus the quality of the binding.
Of particular interest is U.S. Pat. No. 3,907,316 which issued on Sept. 23, 1975 to Marker et al. This patent relates to a method and a device for automatically releasing a ski boot from a ski on which the boot is mounted, in the event of danger to the skier. The forces acting in a skier's leg are continuously monitored and are compared, over a predetermined interval of time, with a threshold value. When the forces reach a predetermined value, related to the threshold value, the ski boot is released from the ski.
In this way U.S. Pat. No. 3,907,316, by introducing a characteristic releasing quantity `pulse`, is able to replace the mechanical elasticity by an electric elasticity which, in comparison with the former, has the advantage of being independent of distance and thus eliminating frictional influences and the like. This is associated with an accurate setting of the binding independent of external influences and remaining unchanged even during prolonged periods of operation.
Even though U.S. Pat. No. 3,907,316 represents a desirable improvement in the art, there is still a need for a method and apparatus for successfully operating an electronic safety ski binding under different marginal conditions such as skiing ability, bone structure of the skier, snow and terrain conditions. The present invention is directed toward filling this need.